Pulverizer mill



2 Sheets-Sheet 1 E. E. LYNCH PULVERIZER MILL Filed Jue 24, 1941 May 4, 1943.

INVENTOR. ERNEST E LY/v ff' ATTORNEY.

May 4, 1943. E, E, LYNCH 2,318,175

PULvERIzER MILL Filed June 24, 1941 2 Sheets-Sheet 2 INVENTOR. ER/vesr E. LYNCH ATTORNE Y.

Patented May 4, 1943 PATENT OFFICE PULVERIZER MILL Ernest E. Lynch, Alameda, Calif., assignor to Thomas P. Baconj, Sr., Oakland, Calif.

Application June 2.4,j 1941, Serial No. 399,478 s claims. (c1. :ss-45) the ground material outwardly and over the` periphery of the bowl, and in which central feeding of the material is facilitated. l5 Another object of this invention is to provide a ball Vmill in which the balls are held betweenv a bowl and a driving race and in which means of connection is provided between the bowl and the driving race to convert the rotation of one into rotary movement of the other but in opposite direction.

Another object of this invention is to provide a ball mill in which the balls are held between removable and replaceable grinding plates posi-"25 tively rotated in opposite directions to each other so as to rotate the balls in such a manner that the entire applied horse power is utilized in the reduction of ore, by reducing frictional resistance and providing opposite diiierential leverages or 'il turning moments to the balls, and thereby increasing the ball speed without the necessity of an increase in centrifugal force in the bowl of the ball mill. W

Another object of this invention is to pr0vide"ff.3 a pulverizer or ball mill which is highly useful and simple in construction. Convenience of arrangement, lightness and comparative inexpense of manufacture are further objects which have been borne in mind in the production and de-f velopment of the invention.

With the foregoing and other objects in View, my invention resides in the combination and arrangement of parts and in the details of construction hereinafter described and claimed, itfbeing understood that .changes in the precise embodiment of the invention hereinafter disclosed may be made within the scope of the appended claims without departing from the spirit of the invention.

The invention is clearly illustrated in the accompanying drawings, wherein:

Fig. 1 is a cross-sectional view of the ball `vFig. 2 is a plan View of the driving headv ofv the ball mill.

Fig. 3 is a plan view of the driving race of the ball mill.

Fig. 4 is aside view of the race of the ball` mill.

Fig. 5 is a removable top race lining.

Fig. 6 is a sectional plan view showing the diiferential transmission in the column of the milling unit, and

Fig. 7 is a sectional fragmental View of the connection between the elements of the milling unit and the driving unit of my machine.

In carrying out my invention I make use of a milling or pulverizing unit II removably journalled in a transmission and support unit I 2 in such a manner that a pulverizer unit can be connected at its top to a suitable lifting mechanism and b e lifted out vertically from the bearing support unit I2.

In detail the bearing support unit I2 includes a base I3 suitably secured or held on a foundation or on the ground. A substantially cylindrical housing I4 is mounted on the base, I3. The top I 6 of the housing is dished from the center outwardly and downwardly and slopes toward a discharge lip I'I at one side thereof. l A cylindrical shield I8 is held on top of the housing I4 so as to inclose a milling or grinding space above the dished top IB.

Inside of the housing I4 is a central hub I9 which is held on the bottom of the housing I4 by a suitably secured ange 2|. The hub I9 is cylindrical. On the hub I9 rests a hub sleeve 22 so that the hub-sleeve 22 is journalled on and rotatable around the hub I9 as an axis. On the upper portion of the hub sleeve 22 is suitably iixed a beveled gear 23 which is in mesh with a gear 24 which latter in turn is driven by a drive shaft 26 extending from the outside into the housing I4 and suitably journalled in a bearing 'is an antifriction trust bearing 33 for supporting the weight of the milling unit I I thereon. The milling unit II has a shouldered stern 34 which fits into said counter bore 3l and hole 29 of the Y standard 28 so as to rotatably journal the pulverizing unit II in said standard. The shoulder 36 "of this stem 34 rests on the trust bearing 33.

The pulverizing unit II has at the bottom of its stem 34 a squared end 3l which slidably'ts -and its dished lining 58 unto is to be noted that the lining pins into a squared bore 38 in the top of Ithe hub sleeve 22 of the driving mechanism in the housing I4. This establishes a separable driving connection between the milling unit I I and the driving mechanism inside the supporting unit I2, which connection can be severed simply by lifting the milling unit Il and its stem 34 out of the standard 28 and out of the hub sleeve 22.

The milling or pulverizing unit II has a bowl 4I mounted on the top of the stem 34. Inside of the bowl 4I is a lining or race 42 which is removably held in place by means of locking grooves 43 around its central aperture 44 which interlock with corresponding radial lugs 46 on the bowl 4I. It is to be noted that the central portion of the bowl 4I and the lining or race 42 are level. The bowl 4I and its lining race 42 are dished upwardly at 41 near the outer periphery thereof. A plurality of balls 48 ride on the dished outer periphery or rim 41 of the bowl lining 42.

From the center of the bowl 4I, extends upwardly a hollow column 49 on the top 5I of which is rotatably held the hub 52 of a driving frame 53. The driving frame 53 has thereon lateral diametrically opposite driving arms 54 which interlock with corresponding slots 56 in the top of -a driving head 51.

A lining or race 58 is provided on the lower face 59 of the driving head 51 so as to engage the balls 481 in such a manner.

as to hold said balls 48 in the dished outer rim 41 of the bowl lining 42.

The driving head 51 is hollow so that its face '59 extends downwardly outside of the upper column 49. The lower end of the driving head 51 ,has an annular seat 6I formed on the inside thereof into which fits a coil spring 62. The

.upper end of the coil spring 62 bears against a complemental seat 63 in the underside of the driving frame 53. The driving frame 53 is also hollow and has spokes 64 connecting the top of its hub 52 to the body thereof from which latter the driving arms 54 project. The hub 52 of the driving frame 53 is shouldered at 61 so as to rest on the top of the column 49. A shaft 68 is journalled in the hollow column 49. The lower end of the shaft has a trust bearing 69 thereon which is in a recess 1| inside of the column 49 so as to prevent upward movement of the shaft E8. The upper end of the shaft 68 is reduced and -is keyed to or otherwise drivingly nts at 12 in the upper portion of the hub 52 of the driving 4-frame 53. A lock nut 13 threaded on the top of the reduced shaft end 12 bears against the top of the driving frame hub 52 so as to hold the -frame 53 against upward movement. In .this

the driving head 51 the balls 48. It 58 has engagement 14 thereon which fit into corresponding holes 16 in the underside of the driving head 51 as shown in Figures 3, 4, and 5, so that the manner the spring 62 urges lining58 is compelled to move with the driving head 51. It is to be also noted that the curvature or dish of the lining 58 is such that it provides a race which is not diametrically opposite. to the dish of the bowl 41 but is offset so that 1 less than 180 of the ball peripheries are between the respective dished races on the side of the balls facing outwardly from the mill. This holds the balls continuously in the outer dished portion of the bowl leaving the central portion of the bowl unobstructed.

On the top of the driving frame 53 is a hopper 11 which aligns with the spaces between the `spokes 64 so as to allowthe ore tondrop through.i

said spaces through the hollow driving head 51 past the outside of the column 49 onto the central portion of the bowl 4I and of the bowl lining 42. A cylindrical screen 18 is held in a groove 18 around the outer periphery of the bowl 4I. The fineness of this Screen 18 determines the degree or ineness of pulverization because the centrifugal force throws the pulverized ore over the rim of the bowl 4I and to the screen 18 and whatever ore is not crushed finely enough to pass through the screen 18 is returned to the bowl 4I for further crushing.

When the milling unit I I is in place in the machine the stem 34 is rotated by the hub sleeve A22 and thus the bowl 4I and the column 49 are rotated together. The shaft 68, the driving frame 53 and the driving head 51 are rotated in opposite direction to that in which the bowl 4I rotates, by means of a differential transmission mechanism 19. It is to be noted that the lower end of the column 49 is enlarged so as to form a central housing. The bowl 4I has a correspondingly opening 8| in its center. In this housing space is disposed the differential transmission 19. A bevel gear 82 has an exteriorly square hub .83 which fits into a square hole 84 in the top of the stem 34 so that the gear 82 rotates with the stem 34 and with the bowl 4I. The bevel gear 82 and its hub 83 are rotatable on a stationary shaft 86. Thisshaft 89 extends through the center of the stem 34 and has a squared lowered end 81 which fits into a squared hole 88 in the hub I9. In this manner the shaft 86 is held stationary and the stem 34 and the gear 92 rotate around said shaft 8B. In the top of the shaft 86 is a square hole 89 into which fits a spider shaft 9 I. Four arms 92 extend from. the top of the spider shaft 9| in a plane at right angles to the axis of rotation of the milling unit and parallel with the face of the gear 82. On the end of the arms 92 are rotatably mounted gears 93 which are in mesh with'the bevel gear 82. A driven bevel gear 94 is in mesh with the gears 93 opposite to the bevel gear 82. The upper bevel gear 94 is secured to the drive shaft 68. When the pulverizer unit is rotated the bevel gear 82 rotates with the bowl 4 I. The bevel gear S2 rotates the vertical gears 93 so as to transmit rotation to the upper bevel gear 94 in a direction opposite to the direction of rotation of the bowl 4I. The bevel gear 94 in turn rotates the drive shaft 68, the upper end 12 of which latter in turn rotates the driving frame 53 so as to rotate the driving head 51 and the upper race 58 in a direction opposite to the direction of rotation of the bowl 4I.

Y In operation the milling unit II is assembled simply by lowering it onto the standard 28 of the base unit I2 so that the stem 34 rests in the standard 28 and the square end 31 of the stem 34 is engaged with the square bore 38 in the driving hub sleeve 22. At the same time the square end 81 of the stationary shaft 86 is engaged with the square hole 88. in the bottom hub I9. Rotation is imparted to the drive shaft 26 in any usual manner such as by means of an velectric motor not shown. The power is transmitted through the gears 24 and 23 to the hub sleeve 22 which latter in turn rotates the stem 34 of the milling unit II. The bowl 4I and the column 49 rotate with the stem 34. At the same time the transmission 19 rotates the upper driving elements and ultimately the driving head 51 and its lining race 58 oppositely to the Vrotation of the bowl 4I.. The ore is fed through the hopper "Il, it falls down along the column 49 to the center of the bowl 4l. Clogging of this intake passage along the column 49 is prevented by the agitating effect produced by the rotation of the column 49 in opposite direction to the rotation of the driving frame 53 and driving head 5l. Centrifugal force carries the ore outwardly on the surface of the bowl lining 42 and to under the balls 4S. rEhe balls 48 are rotated by the tangential forces or turning moments exerted by the bowl lining 42 and the head lining 58 thereon. The dished race of the head lining 58 is closer to the Vertical center plane of the balls 48 than the dish at the outer rim of the bowl lining 42. This angular arrangement eiliciently rotates the balls around axes of rotation converging upwardly toward the center of rotation of the milling unit il. This rotation at this angle increases the centrifugal action on the ore without necessitating the increase of the diameter of the bowl 4I. In other words the movement of the crushed ore toward the screen 'I8 is accelerated and a larger volume of ore can be handled without increasing the size of the machine. 'Ihe rolling of the balls 48 at such convergent angle also reduces frictional resistance and applies greater power to the crushing of the ore. The spring S8 holds the driving head and the head lining 58 yieldably so as to prevent clogging of the machine. Large lumps of ore are quickly dislodged and then ground.

Water is applied in the usual manner and the pulp passing through the screen 18 drops down oi the rim of the bowl 4l and inside of the shield cylinder I3 onto the dished housing top I6. The pulp is discharged by gravity through the opening above the lip Il and onto a usual conveyer or to a machine for performing the next operation on the ore.

The machine operates efliciently. It can be made of comparatively small size yet with comparatively large capacity. For cleaning or repairing it is not necessary to stop the operation entirely because a reserve milling unit I l can be easily placed in position for continued operation.

I claim:

l. A ball mill comprising a frame, a bowl journaled in the frame, a plurality of grinding balls mounted in the bowl, a column extended upwardly from the center of the bowl, a shaft extended through said column, a driving head secured to the upper end of the shaft, said head comprising a hub rigidly secured onl the shaft,

a plurality of arms formed on the hub and extending downwardly therefrom, a ring connecting the lower ends of the arms, a pair of lugs on the ring, a floating head disposed below the driving head and resting on the balls, said floating head having a central hollow hub with recesses formed in the upper end to receive the lugs on the driving head, and annular flange at the lower end of the hub and interiorly thereof to form an annular seat, a spring resting on said annular recesses and engaging the ring of the driving head, said ring exerting a yielding downward pressure on the floating head against the balls, and means for driving the bowl and the shaft extending through the column in opposite directions.

2. A ball mill comprising a frame, a bowl journaled in the frame, a plurality of grinding balls mounted in the bowl, a column extending centrally from the bowl, a shaft extending through the column, a driving head secured to the upper end of the shaft, said head comprising a hub rigidly secured on the shaft, a plurality of arms formed on the hub and extending downwardly therefrom, a ring connecting the lowr ends of the arms, a pair of lugs on the ring, a floating head disposed below the driving head and resting on the balls, said floating head having a central hollow hub with recesses formed in the upper end to receive the lugs on the driving head,

an annular flange at the lower end of the hub and interiorly thereof to form an annular seat, a spring resting on said annularrecesses and engaging the ring of the driving head, said ring exerting a yielding downward pressure on the floating head against the balls, means for driving the bowl column and the shaft extending therethrough in opposite directions, and a feed hopper secured to the driving head, said hopper being adapted to deliver ore to be ground between the arms of the driving head and said ore falling by gravity between the arms and through the ring and the hollow hub down into the bowl.

3. A ball mill comprising a frame, a journal support on the frame, a bowl, a shaft of the bowl being journaled in the journal support with freedom of axial insertion and removal, a central hollow column extended from the bowl upwardly; a driving head rotatably journaled on the column, said driving head comprising a hub, a plurality of arms extended downwardly from the hub, a head connecting the lower ends of the arms, a hollow oating head disposed below said driving head and resting on the balls, driv-v ing connection between the floating head and the driving head, resilient means to urge the floating head against the balls; a transmission mechanism in the column for transmitting and reversing the rotation of the bowl, a shaft extended from said transmission mechanism through said column and drivingly connected to the hub of the driving head, a driving gear of said transmission being rotated with said bowl, a driving mechanism in said frame, and severable connecting means between the bowl shaft and. the driving mechanism.

ERNEST E. LYNCH. 

